Picturebook reading is a common form interaction between parents and young children. This study examined developmental changes and socioeconomic differences in picturebook interactions of mother-infant Argentine dyads. 21 middle and 18 low SES mothers with their 12 to 24 months-old infants interacting with two different books, were observed. If was found that mothers of both SES groups adjusted the level of their demands not only to the task requirements (books) but also to the age of the infant. However, it was also found that the style of the interaction was different depending on the SES of the mother-infant pair. A more demanding and elaborated maternal language along with a linguistically more competent child were found in the middle SES group.